Undiagnosed for over 7 years, TSH 7.5 (range 0.2 to 4.5) in 2007, but GP did not make me aware, despite laboratories recommendation 'borderline' and should be re-tested in 3 to 6 months. 7 years later, feeling absolutely awful (typical hypo symptoms) insisted on another blood test, AND a print out of results to show a specialists. Discovered TSH 8 (last year), so basically TSH 7 to 8 for approx 7 years. Has my heart been affected, and if so, now I'm on NDT, can it return to health, or has it been permanently damaged? I'm female, 54 years old.